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A097701 Expansion of 1/((1-x)^2*(1-x^2)^2*(1-x^3)). 6
1, 2, 5, 9, 16, 25, 39, 56, 80, 109, 147, 192, 249, 315, 396, 489, 600, 726, 874, 1040, 1232, 1446, 1690, 1960, 2265, 2600, 2975, 3385, 3840, 4335, 4881, 5472, 6120, 6819, 7581, 8400, 9289, 10241, 11270, 12369, 13552, 14812, 16164, 17600, 19136 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

MAPLE

with(combstruct):ZL:=[st, {st=Prod(left, right), left=Set(U, card=r), right=Set(U, card<r), U=Sequence(Z, card>=1)}, unlabeled]: subs(r=5, stack): seq(count(subs(r=3, ZL), size=m), m=3..47) ; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 09 2007

PROG

(PARI) a(n)=1/576*(2*n^4+36*n^3+224*n^2+558*n+495+(18*n+81)*(-1)^n-64*(if(n%3, 1, 0)))

CROSSREFS

First differences of A002625. Partial sums of A008763.

Sequence in context: A138226 A175287 A007979 * A056870 A014739 A039946

Adjacent sequences:  A097698 A097699 A097700 * A097702 A097703 A097704

KEYWORD

nonn

AUTHOR

Ralf Stephan, Aug 24 2004

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Last modified February 17 14:50 EST 2012. Contains 206050 sequences.